The present invention relates to missile launchers and more particulary to shock absorbing missile launch pads for use in isolation of MX-type missiles from various environmental interference.
It is known in the art to provide means for protecting a missile from vibrations applied to the mounting structure upon which the missile is adapted. One such device is disclosed in U.S. Pat. No. 4,357,855, in which a liner for lining the interior surface of a canister which carries and supports the launching of a missile includes a first resilient layer, a second thermally reflective layer, and a third layer having a low coefficient of friction. The first layer contacts the inner surface of the canister, the second layer is interposed between the first and third layer, and the third layer contacts the outer surface of the missile. More particulary, the first layer is a resilient layer of supple material, such as rubber. The second layer is reflective and is comprised of a thin foil-type material. The third layer provides low coefficient of friction interaction with the missile outer surface. This third layer is transparent to heat. The second layer reflects heat transmitted through the third layer, such that the device is reusable.
In U.S. Pat. No. 3,124,040, a rubber mat with spaced annular fins is disclosed coated with Teflon or Nylon, and is formed into a tubular sleeve with the fins projecting toward the sleeve's center. It is placed in a missile tube and therein forms a buffer or support system for a missile to be carried within the tube.
One problem with the above prior art, and similiar art, is that these pads fail to reflect the requirements of MX type missile systems. Most notably, the force versus deflection characteristics and mechanical creep requirements of such pads are different in that prior art missiles have contemplated vertical storage. In a MX land based type arrangement such missile is stowed horizontally and is raised to a near-vertical position at launch. Furthermore, the MX environmental specifications also require that the pads have better ozone resistance than in prior art pads.
The creep characteristics of an elastomeric canister-to-missile support pad are influenced by stress history, temperature, base elastomer, filler content, crosslink density, type of crosslink, carbon black, pre-stressing and moisture. Ozone has a significant deleterious effect on some elastomers, such as natural rubber, but this effect may be minimized by application of antidegradants or the like. The present invention was developed in view of these influences.